The environmental prevalence of the tire wear-derived emerging pollutant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) has increasingly raised public concern. However, knowledge of the adverse effects of 6PPD-Q on soil fauna is scarce. In this study, we elucidated its impact on soil fauna, specifically on the earthworm Eisenia fetida. Our investigation encompassed phenotypic, multi-omics, and microbiota analyses to assess earthworm responses to a gradient of 6PPD-Q contamination (10, 100, 1000, and 5000 mu g/kg dw soil). Post-28-day exposure, 6PPD-Q was found to bioaccumulate in earthworms, triggering reactive oxygen species production and consequent oxidative damage to coelomic and intestinal tissues. Transcriptomic and metabolomic profiling revealed several physiological perturbations, including inflammation, immune dysfunction, metabolic imbalances, and genetic toxicity. Moreover, 6PPD-Q perturbed the intestinal microbiota, with high dosages significantly suppressing microbial functions linked to metabolism and information processing (P < 0.05). These alterations were accompanied by increased mortality and weight loss in the earthworms. Specifically, at an environmental concentration of 6PPD-Q (1000 mu g/kg), we observed a substantial reduction in survival rate and physiological disruptions. This study provides important insights into the environmental hazards of 6PPD-Q to soil biota and reveals the underlying toxicological mechanisms, underscoring the need for further research to mitigate its ecological footprint.

The pervasive occurrence of combined metal and antibiotic pollution (CMAP) in agricultural soils is increasingly being recognized as a novel threat to ecosystems. However, the toxicity variations of CMAP compared to single pollution and the mechanisms underlying these changes remain poorly understood. Herein in this study, the toxicities of copper (Cu)/erythromycin (ERY) and lead (Pb)/norfloxacin (NOR) to earthworms (Eisenia fetida) were investigated. These results indicated that a single exposure to ERY and NOR at environmental concentrations had negligible effects on physiological processes. Combined Cu/ERY exposure induced more significant oxidative stress, disrupted energy metabolism, and caused cellular damage than Cu alone, as indicated by altered antioxidant enzyme activities, malondialdehyde and adenosine triphosphate content, elevated reactive oxygen species levels, and apoptosis rates in coelomocytes. Conversely, these adverse effects were mitigated by Pb/NOR exposure compared to Pb treatment alone. Further analysis of the gut microbiota revealed that Cu/Pb-tolerant Bacillus spp. play a critical mediating role in the contrasting toxicity profiles. ERY reduced the abundance of Bacillus spp., diminishing their ability to secrete soluble phosphate to immobilize Cu in the gut and leading to increased Cu absorption and toxicity. NOR enriches Bacillus spp. in the gut, facilitating Pb immobilization and reducing Pb bioavailability and toxicity. The contrast toxicity profile revealed the response of the gut microbiota taxa is the primary determinant of the variation in CMAP toxicity. These findings advance our understanding of the impact of CMAP on soil organisms and highlight the need for comprehensive ecological risk assessments to inform regulatory strategies.

The widespread use of plastic agricultural films necessitates a thorough evaluation of environmental risks posed by soil microplastics (MPs). While the intestinal tract is a critical site for MP interactions in soil organisms, current research predominantly focuses on overall physiological responses, overlooking organ-specific toxic mechanisms. To address this gap, we exposed earthworms (Eisenia fetida) to polyethylene (PE) and biodegradable polylactic acid (PLA) MPs sourced from agricultural films at an environmentally realistic concentration of 1.0 g/kg. Incorporating natural earthworm mobility, we designed two exposure scenarios: migration from clean to contaminated soil (scenario A) and vice versa (scenario B). Machine learning-driven image analysis and phenotypic profiling revealed that PE induced more severe intestinal lesions than PLA, adversely affecting intestinal immune functions. Furthermore, PE resulted in greater oxidative damage and significantly activated immune proteins such as melanin and antimicrobial peptides through reprograming immune-related gene and protein pathways. Conversely, PLA predominantly disrupted intestinal digestive and absorptive functions, though the gut microbial community partially mitigated damage through structural and compositional adaptation. Compared with scenario A, earthworms in scenario B exhibited reduced tissue damage, enhanced digestive enzyme activity, and upregulated energy-related metabolites and cell proliferation genes, indicating partial recovery from MP-induced intestinal dysfunction. These findings elucidate the distinct toxicity mechanisms of conventional and biodegradable agricultural MPs on soil organisms, while the scenario-based approach advances risk assessment by aligning experimental design with real-world ecological behaviors.

Typically, nanoplastics (NPs) are contaminated before entering soil, and the impact of NPs on the biotoxicity of Persistent Organic Pollutants (POPs) they carry remains unclear. This study simulated two environmentally relevant scenarios: singular exposure of benzo[a]pyrene (BaP) in soil and exposure via NPs loading (NP-BaP). Correlation analysis and machine learning revealed that injury in earthworms exposed for 28 days was significantly associated with NPs. Moreover, when the soil exposure concentration of BaP was 4 mg/kg, the NP-BaP group exhibited 10.67 % greater pigmentation than the BaP-only group. Despite the lower biota soil accumulation factor (BSAF) of earthworms in the NP-BaP group, the concentration of BaP in the soil remained at higher levels in the late stages of exposure. This led to NP-BaP inducing a stronger trend of oxidative damage compared to BaP alone. Furthermore, molecular-level studies indicated that the differential preferences of NPs and BaP for damaging antioxidant enzymes were linked to individual oxidative stress responses. This study confirmed that NPs, at non-toxic concentrations, could increase the persistence of BaP's biological toxicity after prolonged exposure, highlighting the potential safety risks of NPs as carriers of POPs to soil organisms.

Hexafluoropropylene oxide dimer acid (HFPO-DA), an emerging perfluoroalkyl substance (PFAS) that is replacing traditional PFASs, has a wide range of industrial applications and has been detected globally in the environment. However, it remains unclear whether HFPO-DA, is genuinely less toxic than perfluorooctanoic acid (PFOA) in terms of soil environmental hazards. Therefore, this study aimed to compare differences in toxicity between PFOA and its substitute, HFPO-DA, in a common species of earthworm, Eisenia fetida. Our findings revealed that both HFPO-DA and PFOA caused oxidative damage, apoptosis, reproductive disorders, and neurotoxicity in E. fetida at a concentration of 0.2 mg/kg following exposure for 28 d. Specifically, at the molecular level, PFOA resulted in a significant decline in total antioxidant capacity and lipid peroxidation, whereas HFPO-DA did not have the same effect. The Integrated Biomarker Response (IBR) index, based on the indicators studied, showed that HFPO-DA exhibited lower toxicity than PFOA. The transcriptomic results suggest that HFPO-DA can induce neurotoxicity, similar to PFOA; however, the specific mechanisms differ. Although HFPODA appears to be less toxic than PFOA to E. fetida, its potential hazards at the transcriptional level, affecting different pathways, require further investigation. This study provided new insights into the safety of HFPO-DA as a novel substitute for PFOA.

As a class of emerging persistent organic pollutants (POPs), per- and polyfluoroalkyl substances (PFASs) are widely detected in the soil environment, posing a significant threat to the soil ecosystem and human health. Therefore, it is necessary to study the ecotoxicological effects of PFASs in soil. In this study, we conducted a comprehensive review of the toxic effects of PFASs on earthworms at the individual and sub-individual levels, including survival status, body weight, reproduction, oxidative damage, genes, metabolism, and so on. Results showed that earthworms exposed to certain concentrations of PFASs display various pathological symptoms on their body surfaces, a decrease in body weight and reproductive rate, and even death. The LC50 values of PFOS to earthworms (365-1404 mg/kg) are consistently lower than those of PFOA (544-1307 mg/kg) under the same exposure condition, indicating a higher toxicity of PFOS compared to PFOA. At the sub-individual level, PFASs may induce oxidative stress, DNA damage, aberrant gene expression, and metabolic disruption in earthworms. PFOS induced disruption of the nervous and metabolic system, PFHxS disrupted energy balance and elicited inflammation, and PFBS induced cell apoptosis in earthworms. Compared to PFOS, PFHxS may induce a greater degree of oxidative stress and damage, and 6:2 Cl-PFESA (F-53B) exhibited a greater propensity to disrupt the extracellular matrix and induce cellular ferroptosis and apoptosis in earthworms. At environmentally relevant concentration levels, PFOA induces significant dysregulation of pathways related to amino acid, energy, and sulfur metabolisms within earthworms. Bioavailability and bioaccumulation capacity of PFASs are important factors in determining their toxicological effects in soil, which is influenced by the molecular structure of PFASs and the combined effects of various environmental factors, such as soil organic matter composition and content, pH, PFAS concentrations and exposure duration. Finally, existing research deficiencies and future directions about the toxicological research of PFASs on earthworms are proposed, aiming to offer reference for ecological risk assessment of PFASs-contaminated soil.

Soil is an important sink for microplastics (MPs) and pesticides. MPs can act as carriers for pesticides, thus induce direct and indirect effects on soil organisms. Fluindapyr (FIP), a novel succinate dehydrogenase inhibitors fungicides (SDHIs), may pose a serious threat to earthworms. However, few studies have evaluated the effects of joint exposure to MPs and FIP. Here, earthworms (Eisenia fetida) were jointly exposed to PMMA (polymethylmethacrylate) and PS (polystyrene) MPs of different sizes (0.1, 1 and 10 mu m) along with FIP for 28-day to investigate the toxic effects of single and joint exposure of FIP and MPs on earthworms. The results showed that joint exposure to 0.1 and 1 mu m MP promoted the accumulation of FIP in earthworms at the beginning of the experiment compared to the sole group, but the elimination of FIP from earthworms accelerated after 14 d. In addition, the joint exposure caused more serious damages to the epidermis and intestine of earthworms and increased the severity of oxidative stress. The effects of joint exposure to FIP and MPs depended on the size of the MPs, and the strongest effects were observed in the treatment with the smallest size. The 16S rRNA sequencing results showed that the joint exposure to MPs and FIP didn't cause gut microbiota dysbiosis. However, the sole 0.1 mu m PS significantly altered the community diversity and richness of earthworm gut bacteria, and the relative abundance of Proteobacteria, Actinobacteria and Firmicutes was significantly changed. The obtained results inferred that MPs could influence environmental and toxicological behaviors of FIP and may provide data support for the risk assessments of MPs and FIP on soil ecosystems.

The high global production combined with low recycling rates of polystyrene (PS) and low-density polyethylene (LDPE) contributes to the abundance of these commonly used plastics in soil, including as microplastics (MPs). However, the combined effects of MPs and heavy metals, such as arsenic (As) on earthworms are poorly understood. Here, we show that neither PS nor LDPE altered the effects of As on the survival, growth, and reproduction of the earthworm Eisenia fetida. As stress, both alone and in combination with the MPs, induced DNA damage in coelomocytes. In As-exposed earthworms, PS and LDPE increased the accumulation of reactive oxygen species while the activities of the antioxidant enzymes peroxidase, superoxide dismutase, and catalase were significantly lower under combined PS/LDPE + As exposure than under As exposure alone. As stress alone reduced cocoon production and the mRNA level of the reproduction-related gene ANN whereas As combined with PS/LDPE reduced the mRNA levels of CYP450, an enzyme involved in detoxification. Integrated biomarker response analysis revealed that PS/LDPE did not significantly impact the overall ecotoxicological effects of As exposure on earthworms. This study provides important insights into the potential ecological risks of MPs in heavy-metal-contaminated soil.

Strong soil-tool adhesion on soil-engaging components is a key factor leading to the energy consumption and agricultural tool damage in agriculture tillage. A number of chemical and physical strategies have been widely proposed to eliminate soil-tool adhesion, but subjecting to limited anti-soil capabilities. In this work, we present an earthworm-inspired matter-repellent surface by stably grafting dimethyl dimethoxy silicane and infusing silicone oil, allowing for a superior resistance to soil-steel adhesion in an eco-friendly mode. The presence of such coating enables a theoretical adhesion work reduction by 10 times, thereby resulting in robust repellency to stick soil. Furthermore, the influence of water fraction in soil, adhesion velocity, and adhesion angle on the anti-soil performance of matter-repellent surfaces are fully revealed to guide its potential application in agricultural tools. It is anticipated that incorporating our matter-repellent coating into soil-engaging components is beneficial to the development of agricultural machinery.

This study systemically investigated the enantioselective bioaccumulation and degradation of etoxazole (ETZ) in earthworms along with the transcriptome and oxidative stress responses to ETZ enantiomer exposure. Based on the M-shaped bioaccumulation trends for ETZ enantiomers, R-ETZ was found to be preferentially bioaccumulated in earthworms. Sublethal toxicity analysis showed that S-ETZ induced greater changes in protein content, malondialdehyde content, detoxifying metabolic enzyme activity, and oxidative stress in earthworms, compared to those induced by R-ETZ. Integrated biomarker response analysis suggested that S-ETZ induced higher sublethal toxicity in earthworms than R-ETZ. Finally, transcriptomic analysis indicated that 845 and 314 genes were differentially expressed after R-ETZ and S-ETZ exposure, respectively, when compared to the nonexposed control group. Enrichment analysis indicated that these differentially expressed genes were primarily enriched in the digestion and absorption of proteins, lysosome, peroxisome, and peroxisome proliferator-activated receptor signaling pathways. These results suggest that earthworms exhibit distinct enantioselective responses to S-ETZ and R-ETZ. This study elucidates the enantioselective bioaccumulation, degradation, transcriptome, and oxidative stress characteristics of ETZ enantiomers in earthworms at the enantiomer level, offering a theoretical foundation to improve the risk assessment of ETZ in the soil-earthworm microsomes.